Coupling coil



Patented Jan. 14, 1936 UNITED STATES PATENT. OFFICE George W. Fyler, Schenectady, N. Y., assignor to General Electric Company, a. corporation of New York Application March 14, 1934, Serial No. 715,468

7 Claims.

My invention relates to coupling coils, or transformers, and more particularly to such coils adapted foruse in high power high frequency equipment, as, for example, in the output circuits of broadcast transmitters.

One of the objects of my invention is to provide such a coil in which the tuning of the output circuit to which it is connected may be conveniently effected by variation of the coil while maintaining the incidental variation in coupling between the diierent windings of the coil at a minimum.

A further object of my invention is to provide such a coil in which the coupling between the different windings may be readily adjusted to compensate for any variation thereof produced by the tuning operation referred to and also to permit of adjustment of the circuit loading.

A further object of my invention is to provide such a coupling coil, which in a single unit, includes means continuously variable over desired ranges for the purposes of substantially independent variation of both coupling and tuning and which at the same time is of extremely simple and economical construction.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing in which the single gure represents an embodiment of my invention.

Referring to the drawing, I have shown therein a coupling coil comprising windings I and 2 arrangedv on opposite sides of a capacitance shield 3. Coils I and 2 are of the so-called pancake construction, each coil comprising a plurality of concentric turns, or turns arranged in a spiral in a common plane, these turns being made up of heavy conductor of high current carrying capacity. The windings of the coil may be circular as shown, elliptical, rectangular, or of other suitable shape as desired. The terminals of coil I are indicated at 4 and 5 and may lead to the high frequency source, such for,

example as the condenser of the tuned output circuit of a high frequency transmitter the inductance of which tuned output circuit comprises the coil I. To vary the tuning of the circuit comprising the coil I a portion 6 of one of the turns of this coil is arrangedto be rotated about an axis substantially in the plane of the coil. It will be noted that this portion 6, which is substantially one-half of a turn, is pivoted both at the top and at the bottom of the coil, the pivot members being supported upon the end of a non-conducting bar l which extends transversely of the coil. The lower portion of the half turn 6 is rigidly connected to a rotatable shaft 8 which includes a non-conducting portion 9 provided at its ends with corona shields III whereby the lower portion of the shaft is insulated from the highpotential, which may be impressed upon the coil. A worm wheel II is connected to the shaft 8 and is arranged to be rotated by means of a worm I2 and control handle I3. By rotation of the handle I3 the half turn 6 may be rotated from a position on the far side of the coil as shown, but which is sulciently removed from the plane of the coil to permit the terminal 4 to be brought out, to the position shown which is substantially at right angles to the coil, and thence onward to a position at the left side of and substantially in the plane of the coil. In the first of the two positions it will be seen that the inductive effect of the half turn 6 is in aiding relation to that of the remaining portion of the coil. In the latter position at the lefthand side of the coil the inductive effect of the half turn 6 opposes that of the remaining portion of the coil. Thus by rotation of this half turn the inductance of the coil may be varied by approximately the amount of the inductance of a full outer turn of the coil. The outer turn of the coil is chosen for use in effecting this inductance adjustment since owing to its increased length it has maximum inductance thereby increasing the amount of inductance variation possible.

The coupling effect between the two coils due to rotation of the half turn 6 is effected to some extent but this effect is small owing to the position of the half turn 6 with respect to the coil 2. To compensate for such eect upon the coupling between the two windings, as is produced by rotation of the half turn 6, and also to permit of proper adjustment of the loading of the circuits, one of the windings is made adjustable in position with respect to the other. In the embodiment shown the coil 2 is illustrated as mounted upon a frame I3 which is hinged at its lower extremities I4 so that it may be rotated about an axis in the plane of the coil and substantially below the coil whereby it may be moved to and from the winding I. To effect this adjustment, and to retain the winding 2 in a desired position, members i5 are attached to the top of the framework and are connected together by rod l@ which is arranged for back and forth movement by means of an arm l and wormwheel l. The latter is arranged' for rotation by means of a worm t@ and control handle 2t. By rotation of the control handle the rod i6 is moved forward and backward with respect to the coil thereby varying the spacing between the two windings to ei'ect any desired adjustment of the coupling therebetween. This adjustment is of course continuous as distinct from a step by step adjustment and may be eiected over any desired range.

For purposes of simplicity of the drawing the output circuit, or transmission line. which may be connected to the winding 2 is not illustrated. Similarly the supporting structure for the wind= ing l is omitted. While preferably the latter coil is supported in xed position, it may, if desired be arranged for adjustable spacing beE tween the windings in a'manner similar to that described in connection with winding 2.

While l have-shown a particular embodiment of my invention iti/vill be understood that I do not wish to be limited thereto since clierent modifications may be made, and I contemplate by the appended claims to cover any such modiiications as fall within the true spirit and scope oi my invention,

What l claim as new and desire to secure by Letters Patent of the United States, is:

l. in combination, an inductance coil comu prising a plurality of turns arranged in a common plane, and means to rotate a portion of one of said turns relative to the other turns.

E. ln combination, an inductanoe coil com= prising a plurality of turns of conductor arranged in. a spiral in a single planeand means to rotate a portion of a turn of said coil about an axis substantially in said plane.

3. Tile combination of a pair of coils, each of said coils comprising a conductor arranged in a conm/ion plane, 'said coils being arranged side by side, and means to rotate a portion of a oi one of said coils about an axis subaoaaeei stantially in the plane of the respective coil thereby to vary the inductance of said coil while maintaining the variation of coupling between said coils at a minimum.

4. The combination of a pair of coils, each of said coils comprising a conductor arranged in a single plane, said coils being arranged side by side, and means to rotate a. portion of a turn of one of said coils about an axis substantially in the plane of the respective coil thereby to vary the inductance of said coil while maintain ing the variation oi coupling between said coils at a minimum, and means to rotate one of said coils about an axis in its respective plane and substantially removed from the respective coil thereby to vary the coupling between said coils.

5. In combination, a pair of pancake coils arranged side by side, means to rotate a portion of a turn oi' one of said coils about an axis substantially in the plane of the respective coil,

and means whereby the distance between said coils is continuously variable over a certain range whereby any variation in coupling be-a tween said coils produced by' rotation oi said portion of a turn may be compensated of correspondingly spacing said coils.

6. In combination, an inductance coil comprising a plurality of turns arranged in a plana, and means comprising a portion of one turn of saidcoil rotatable about an axis substantially in said plane and through substantially 186 de grees with respect to the remaining turns of said coil for changing the self-inductance of said coil by a value substantially equal to the increase in self-inductance of said coil caused by one turn of said coil.

7. The combination of a irst coil and a secr ond coil, said first coil comprising a conductor arranged in a single piane, said coils being are ranged side by side, and means to rotate a pora 40 tion of a turn of said first coil about an axis substantially in the plane of said first coil to vary the inductance of said rst coil while maintaining the variations of coupling vbetween said coils at a minimum.

GEORGE W. FYLER. 

